This invention relates to a vacuum device particularly adaptable for forming a descriptive pattern on a material by utilizing an energy beam and observing and measuring the material by the use of the energy beam.
A conventionally known vacuum device generally comprises a vacuum working chamber in the shape of a box which effects a predetermined process to a material such as a substrate, and a vacuum prechamber also in the shape of a box which carries out the changing operation of the material in the working chamber while maintaining the vacuum condition. Both vacuum chambers are communicated through a communicating member which is provided with valve means for performing the communication between both the vacuum chambers.
The working chamber is provided with an electronic gun for processing material such as substrate disposed in the vacuum chamber and the electronic gun emits an energy beam such as electronic ray to the material to form the descriptive pattern on the surface of the material.
The thus processed material is then transferred into the vacuum prechamber now in a state of atmospheric pressure, and the prechamber is then closed to carry out the following vacuuming operation. At this time, the vacuum state in the working chamber is maintained by closing the vacuum valve means. When the vacuum state in the prechamber is obtained, the valve means is opened to communicate both chambers through the communicating member to thereby transfer the material in the prechamber into the working chamber to a predetermined position. The valve means is thereafter closed and the energy beam is emitted from the electronic gun to the material in the working chamber to carry out a process such as for forming the descriptive pattern to the material. After the completion of this process, the valve means is opened to return the processed material in the prechamber and the valve means is then closed. The vacuum state in the prechamber is thereafter released and the material is taken out from the prechamber when the interior of the prechamber reaches the atmospheric condition.
In order to attain the series of high speed treatment or process described above, it has been proposed to carry out the simultaneous treatment processes in both the working chamber and the prechamber to significantly reduce the processing time.
However, in the vacuum device particularly for a semiconductor apparatus, it is a most significant problem to shorten the turn-around time to treat materials in, for example, a sheeting procedure therefor. Namely, in the vacuum device of the construction described above, the batch processing is usually carried out, so that when one batch includes ten sheets of the materials and about 30 minutes are required for the treatment of one material, at least 300 minutes are required till the materials of one batch treated have been taken out from the vacuum device, requiring a considerably long time including waste time. Therefore, the sheeting procedure becomes a significant problem for the improvement of the turn-around time.
With conventional vaccum devices, however, there is a problem for the sheeting procedure in that the vacuuming operation, leaking operation, material exchanging operation with respect to the prechamber are carried out considerably frequently, thus requiring much time and labour.
In order to eliminate such a problem, it may be possible to carry out parallel processing in the working chamber and the prechamber. However, for example, when the descriptive pattern formation is carried out in the working chamber and the vacuuming, leaking and exchanging operations are performed in parallel in the prechamber, and various vibrations caused by the operations in the prechamber are transmitted to the working chamber, resulting in the inferior descriptive performance in the working chamber.